Step 1: Cook the Farro: In a medium pot, bring 6 cups of salted water to a rolling boil. Add the rinsed farro and cook for 20-30 minutes, or according to package directions, until tender but still chewy. Drain thoroughly and spread the cooked farro on a baking sheet to cool completely.
Step 2: Blanch the Green Beans: While the farro cooks, prepare a large bowl of ice water. Bring a separate pot of salted water to a boil. Add the trimmed green beans and cook for 2-3 minutes until crisp-tender and bright green. Immediately transfer them to the ice bath to stop the cooking process. Once cooled, drain well and pat dry. Cut into 1-inch pieces if not already done.
Step 3: Prepare Remaining Vegetables: Halve the cherry tomatoes. Finely chop the red onion and fresh parsley.
Step 4: Make the Dressing: In a small bowl or jar, whisk together the extra virgin olive oil, fresh lemon juice, Dijon mustard, minced garlic, dried oregano, salt, and black pepper. Taste and adjust seasoning as needed.
Step 5: Assemble the Salad: In a large mixing bowl, combine the cooled farro, blanched green beans, halved cherry tomatoes, and chopped red onion.
Step 6: Dress and Toss: Pour the prepared lemon-herb dressing over the salad ingredients. Toss gently to ensure everything is evenly coated.
Step 7: Add Herbs and Chill: Stir in the fresh chopped parsley. Cover the green bean and farro picnic salad and refrigerate for at least 30 minutes, or preferably a few hours, to allow the flavors to meld. Give it another gentle toss before serving.